Most Leatherman multi-tools include a serrated locking blade. Leatherman blades range in size from 58mm to 75mm (2.25" to 3"), depending on the overall size of the tool. When the serrated blade is the only blade, it is usually serrated at the base, and smooth at the tip. When it is the second blade, it is fully serrated.
A serrated blade is midway between a regular blade and a saw. It cuts through many soft materials more quickly than a regular blade, since you can saw back and forth and have the serrations "dig in" to the material.
NOTE: Sharpen the serrated portions of this blade carefully with a round or triangular file, and maintain the same angle (don't work on the back of the blade). A chainsaw file works well. Be sure to use extra caution with the serrated blade: it will cause much more serious injuries than a straight blade.